Process of making platinum-covered pins.



G. H. KERK.

PROCESS OF MAKING PLATINUM COVERED PINS.

APPLICATION FILED MAR. 3 1 1 9 1 3.

1 81,45 l. Patented Dec. 16, 1913.

other elements.

CHARLES H. KERK, 0F WAYNE, PENNSYLVANIA.

PROCESS OF MAKING PLATINUM-COVERED PINS.

Specification of Letters Patent.

Patented Dec. 16, 1913.

Application filed March 31, 1913. Serial No. 757,958.

specification.

The object of my invention is to improve the manufacture of platinumcovered pins so as to insure the inclosing of the core with platinum.

The invention is particularly applicable for use in the manufacture ofpins for dental purposes, such, for instance, as those which areemployed to hold artificial teeth to their base. It will be understoodthat a pin of this type can be used for other purposes without departingfrom the essential features of the invention.

In the accompanying drawings :Figure 1 is a side view of a dental pinmade in accordance with my invention; Fig. 2 is a sectional view of thepin; Figs. 3 to 8, inelusive, are views illustrating different steps inthe process of making the pin; Fig. 9 is a transverse sectional view onthe line a-a, Fig. 5 Figs. 10 and 11.are views illustrating the processof making a different form of pin; and Fig. 12 is a view showing amodification of the method of reducing the ends of the pins.

Platinum covered pins have been used extensively for dental purposes andwhile the body portion of the core has been protected by the platinumcasing, the ends have always been exposed. By my improved process thepins are finished and the core is entirely inclosed by the platinumcovering. I The objection to the use of pins for dental purposes madeentirely of an alloy of metal other than platinum, or a pin partlycovered with platinum, has been that the alloy or core has been exposedto the acids otthe mouth causing injury to the pins.

The pin of my invention has all of the advantages of a solid platinumpin at a greatly reduced cost.

In carrying out my invention, T first plate, or otherwise cover, a corewhich is preferably made of an alloy, such, for instance, as nickel ormanganese, or combinations of After the core has been covered with theplatinum, as in Fig. 3, I reduce the pin 1, as indicated in Fig. 4, toform a head 2 at each end. These heads may be shaped in any manneraccording to the type of pin desired. In some instances, the pin mayhave but a single head, or, as in F igs. l0 and 11, it may be plainandof an even diameter throughout. The material between the heads ofadjoining pins is then gradually reduced, preferably by the hammering,rolling, or swaging process, until a thin coupling is formed, as shownin Fig. 5. This coupling is then broken, leaving an exposed portion ofthe core surrounded by an annular flange 3, as in Fig. 6. I then remove,or reduce, the projecting portion of the core by mechanical means or byapplying an acid, such as nitric acid, which will dissolve theprojecting end of the core, leaving the blank, as shown in Fig. 7 wit-hthe flange 3 extendingbeyond the core a sufficient distance so that whenthe flange is turned down, it will completely inclose the core. The nextstep in the process is to turn down the flange, as in Fig. 8, byhammering, spinning, or burnishing, making apin with a core entirelyinclosed by a platinum covering. This construction is especiallyapplicable for dental work.

Difficulty nas been experienced in making the proper junction of the pinwith the porcelain of the tooth, due to the fact that, in manyinstances, the core was exposed at the ends and, in some instances, gasbubbles would form in a tooth at the exposed end of the core and make animperfect union between the pin and the tooth. It will be seen that I amenabled to completely inclose the core of a platinum covered pin,protecting the core and making a finished article which is particularlyadapted for use in dental work.

I claim:

1. The process herein described, of making platinum coated pins; saidprocess consisting in covering a core with platinum; indenting the pinat intervals to reduce its diameter; severing the pin at the reducedportions; and then turning over the plati-- num covering onto theexposed portion of the core.

2. The process herein described, of making platinum coated pins; saidProcess consisting in covering a. core with platinum; making annularindentations at intervals in the core and its platinum covering;severing the pin at the reduced portions, leaving an annular flange ofplatinum surrounding the exposed portion of the core, then apply- 'ingan acid to the exposed portion of the core to remove the projectingportion thereof; and turning down the flange onto the core, therebyinclosing the end of the core and making a completely covered article.

3. The process herein described, of manufacturing platinum coated dentalpins; said process consisting in covering a core with platinum; pressingthe core at intervals to form annular projections and making a deeprecess between the two adjoining projections; severing the core and theplatinum covering at the depressions, leaving the reduced portion of thecore exposed surrounded by a flange of platinum; reducing the projectingportion of the core; and turning down the flange onto the core so as toentirely inclose the core within the platinum covering;

In testimony whereof, I have signed my name to this specification, inthe presence of two subscribing witnesses.

CHARLES H. KERK. Witnesses WM. E. Snore,

A. BARR.

